Comment by accessvector

Consider this:

    struct pinsyscall entries[] = {
        { .sysno = 1, .offset = 0x1234 },
        { .sysno = 2, .offset = 0x5678 },
        { .sysno = 1, .offset = 0x9abc }
    };

Now `nsyscalls` will be 3 and `pin` will be an array of 3 ints, initialised to `{ 0, 0, 0 }`.

When we loop through, we'll set:

    1. `pin[syscalls[0].sysno] = 0x1234` => `pin[1] = 0x1234`
    2. `pin[syscalls[1].sysno] = 0x5678` => `pin[2] = 0x5678`

Now when we come to 3, we'll find `pin[syscalls[2].sysno] != 0` since `syscalls[2].sysno == syscalls[0].sysno` - so we set `pin[1] = -1` instead of `0x9abc`.